The downward spiral
The problem is not that we have our own issues. They are there all right - we can't get rid of them by magically snapping our fingers or wishing them away. The problem begins when we start using our own unresolved issues as an excuse for each of our character flaws and personal failures. At that point, there's little to no incentive to fix things up - as long as we have issues, we have excuses - and the downward spiral inevitably looms ahead.
This is usually the moment when friendship is defined by a slap in the face and a "snap out of it" shout, but as far as I am concerned - and as sorry as I am - that's not my duty anymore.